document.write()

Warning: Use of the document.write() method is strongly discouraged.

As the HTML spec itself warns:

This method has very idiosyncratic behavior. In some cases, this method can affect the state of the HTML parser while the parser is running, resulting in a DOM that does not correspond to the source of the document (e.g. if the string written is the string "<plaintext>" or "<!--"). In other cases, the call can clear the current page first, as if document.open() had been called. In yet more cases, the method is simply ignored, or throws an exception. Users agents are explicitly allowed to avoid executing script elements inserted via this method. And to make matters even worse, the exact behavior of this method can in some cases be dependent on network latency, which can lead to failures that are very hard to debug. For all these reasons, use of this method is strongly discouraged.

Therefore, avoid using document.write() — and if possible, update any existing code that is still using it.

The document.write() method writes a string of text to a document stream opened by document.open().

Note: Because document.write() writes to the document stream, calling document.write() on a closed (loaded) document automatically calls document.open(), which will clear the document.

Syntax

write(markup)

Parameters

markup

A string containing the text to be written to the document.

Return value

None (undefined).

Examples

<html>

<head>
  <title>Write example</title>

  <script>
    function newContent() {
      document.open();
      document.write("<h1>Out with the old, in with the new!</h1>");
      document.close();
    }
  </script>
</head>

<body onload="newContent();">
  <p>Some original document content.</p>
</body>

</html>

Notes

The text you write is parsed into the document's structure model. In the example above, the h1 element becomes a node in the document.

Writing to a document that has already loaded without calling document.open() will automatically call document.open(). After writing, call document.close() to tell the browser to finish loading the page.

If the document.write() call is embedded within an inline HTML <script> tag, then it will not call document.open(). For example:

<script>
  document.write("<h1>Main title</h1>")
</script>

Note: document.write() and document.writeln do not work in XHTML documents (you'll get an "Operation is not supported" [NS_ERROR_DOM_NOT_SUPPORTED_ERR] error in the error console). This happens when opening a local file with the .xhtml file extension or for any document served with an application/xhtml+xml MIME type. More information is available in the W3C XHTML FAQ.

Note: Using document.write() in deferred or asynchronous scripts will be ignored and you'll get a message like "A call to document.write() from an asynchronously-loaded external script was ignored" in the error console.

Note: In Edge only, calling document.write() more than once in an <iframe> causes the error "SCRIPT70: Permission denied".

Note: Starting with version 55, Chrome will not execute <script> elements injected via document.write() when specific conditions are met. For more information, refer to Intervening against document.write().

Specifications

Specification
HTML Standard
# dom-document-write-dev

Browser compatibility

BCD tables only load in the browser

See also